4140 Hex Bar Availability/Substitute
4140 Hex Bar Availability/Substitute
(OP)
Have been using a 5/16" hex 4140 steel bar for 2 yrs and now can't locate. The bar is used as an input shaft and must be heat treated to Rc 20-26 and straightened within .020 in a 15" length.
Does anyone know where I can find this material?
An alternate of 12L14, heat treated to same hardness has been proposed. Would this be an equivalent substitute? Do not have any experience with HT 12L14. Would it be more or less likely to warp?
Does anyone know where I can find this material?
An alternate of 12L14, heat treated to same hardness has been proposed. Would this be an equivalent substitute? Do not have any experience with HT 12L14. Would it be more or less likely to warp?





RE: 4140 Hex Bar Availability/Substitute
I'm not sure 12L14 will respond to heat treat in the same manner as 4140. You should check this out.
RE: 4140 Hex Bar Availability/Substitute
AISI 1144 is typically supplied in hex and can be Q & T at 1000F to HRC 30 so maybe 1200F tempering temperature would give you 20-26. Straightness should not be any more problem than 4140 since 1144 can be oil quenched. One problem is that the supplier I am looking at does not stock it in 5/16 hex. 1144 is a free machining grade but not as mchinable as 12L14.
AISI 1045 is supplied in hex but again no listing for 5/16. But maybe another vendor would stock it. It can be water quenched and tempered at 1000F for HRC 22. Water quenching will induce more distortion but since you are straghtening anyway this should not present a big problem.
RE: 4140 Hex Bar Availability/Substitute
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RE: 4140 Hex Bar Availability/Substitute